1. Technical Field
The present invention relates to a method of manufacturing an inertial sensor.
2. Description of the Related Art
Recently, an inertial sensor has been used as various applications, for example, military such as an artificial satellite, a missile, an unmanned aircraft, or the like, vehicles such as an air bag, electronic stability control (ESC), a black box for a vehicle, or the like, hand shaking prevention of a camcoder, motion sensing of a mobile phone or a game machine, navigation, or the like.
The inertial sensor generally adopts a configuration in which a mass body is adhered to an elastic substrate such as a membrane, or the like, in order to measure acceleration and angular velocity. Through the configuration, the inertial sensor may calculate the acceleration by measuring inertial force applied to the mass body and may calculate the angular velocity by measuring Coriolis force applied to the mass body.
In detail, a scheme of measuring the acceleration and the angular velocity using the inertial sensor is as follows. First, the acceleration may be calculated by Newton's law of motion “F=ma”, where “F” represents inertial force applied to the mass body, “m” represents a mass of the mass body, and “a” is acceleration to be measured. Among others, the acceleration a may be obtained by sensing the inertial force F applied to the mass body and dividing the sensed inertial force F by the mass m of the mass body that is a predetermined value. Further, the angular velocity may be obtained by Coriolis force “F=2 mΩ×v”, where “F” represents the Coriolis force applied to the mass body, “m” represents the mass of the mass body, “Ω” represents the angular velocity to be measured, and “v” represents the motion velocity of the mass body. Among others, since the motion velocity V of the mass body and the mass m of the mass body are values known in advance, the angular velocity Ω may be obtained by detecting the Coriolis force (F) applied to the mass body.
In order to measure the acceleration and the angular velocity in the above-mentioned scheme, the inertial sensor according to the prior art adopts a configuration in which a mass body is adhered to a flexible member such as a diaphragm, or the like, as disclosed in Japanese Registration Patent No. 4216525.
However, in the inertial sensor according to the prior art, since the mass body is formed of silicon, the mass body has relatively low density, such that a signal to noise ratio is low. Therefore, sensitivity of the inertial sensor is deteriorated. In order to solve this problem, the density of the mass body should be increased. However, a method of manufacturing an inertial sensor by a precise process while increasing density of a mass body has not been present until now.